Traditional combustion engine power plants in cars can also be used to provide nominal amounts of alternating current (AC) electrical power through the use of an inverter circuit. In the most typical applications, the AC electrical power generated by standard combustion engines is utilized to sustain the electrical needs of the car and its accessories. This generation capability has additionally led to the widespread deployment of “convenience outlets,” which are now used to power computers, video games, cell phones, and the like.
While generation of AC electrical power is possible, it is difficult to obtain significant amounts of useful electrical power from standard combustion engines because the combustion engine exhibits relatively low conversion efficiency. Additionally, since most combustion engines require significant cooling during operation, extended operation of the engine to generate electricity will require the type of airflow usually generated during vehicle locomotion. Finally, environmental considerations such as air emissions and engine noise make automobiles with traditional combustion engines poor candidates for any meaningful levels of power generation, particularly to power the types of electrical loads not directly associated with the vehicle.
Certain new types of vehicles, known as hybrid vehicles, employ a combustion engine coupled with a combination electric motor-generator in order to provide vehicle locomotion. In some of these hybrid or mild-hybrid powertrain systems, an electric motor-generator system replaces the conventional starter motor and alternator. When the hybrid vehicle is decelerating or is stopped, the fuel flow to the engine is shut off, thereby improving fuel economy. The motor-generator system of the hybrid vehicle is implemented to enable this fuel cutoff feature while minimally affecting drivability. As with the conventional combustion engine, the power plant in hybrid vehicles can also be used to provide AC power for convenience outlets and other electrical requirements associated with the hybrid vehicle. However, as with traditional combustion engines, the present AC power generating capabilities of hybrid vehicles are limited in both scope and application.
In view of the foregoing, it should be appreciated that it would be desirable to provide methods for adapting the on-board components of a hybrid vehicle to generate electrical power for use in applications not directly related to the operation of the hybrid vehicle, i.e., off-vehicle loads. It is also desirable to provide electrical power for both balanced and unbalanced loads, as well as support for three-phase and single-phase voltages. Furthermore, additional desirable features will become apparent to one skilled in the art from the foregoing background of the invention and following detailed description of a preferred exemplary embodiment and appended claims.